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Scabies (cont.)

How Do Health-Care Professionals Diagnose Scabies?

Most cases of scabies are diagnosed by describing the symptoms to the doctor who will examine the skin. There is no blood test for scabies, and delays in diagnosis or misdiagnosis are common in low-prevalence areas.

  • Sometimes, the doctor will do a skin scraping to make or confirm the diagnosis. This is performed by placing a drop of oil or saline on top of an affected area of skin. The area is scraped lightly and the scraping is placed on a slide to examine under a microscope. The doctor will look for the mite or its eggs or feces.
  • The doctor may perform a felt-tip-marker test by drawing a washable felt-tip marker across the rash and then wiping it off with alcohol. This may help to identify a burrow because the ink penetrates deep into the skin.
  • Often, there are very few mites that can be hard to find. Therefore, even if the scrapings are negative, the doctor may still recommend treatment if he or she is very suspicious that scabies is present.

Other conditions are sometimes confused with scabies. The scabies mite has no relation to body lice, although the symptoms may be similar. Scabies is sometimes confused with bedbug bites, but in contrast to scabies, bedbugs are visible to the naked eye and can live for long periods of time without feeding. Chiggers are a type of mite that can feed off human blood, but unlike scabies, they are acquired through contact with vegetation and feed for only a few days. Less commonly, the rashes of other skin diseases such as ringworm, shingles, eczema, allergic reactions (hives), jock itch, or impetigo may be confused with that of scabies.

Medically Reviewed by a Doctor on 2/22/2016

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Scabies »

Human scabies is an intensely pruritic skin infestation caused by the host-specific mite, Sarcoptes scabiei var hominis.

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